All wire scrapes have timer starting and the option of manual control. The barrier detection is based either on a mechanical limit switch or motor current measurement. The Comfort model additionally comprises the option of being able to dictate the site to which the scrape is driven after its working movements have been completed as well as to increase safety with a proximity function of the cross channel.
Some of the control centres also have a frost watch which will bypass timer starting if the temperature falls below a programmed frost limit. In this case, the scrape will move either constantly or in bursts of a few metres at a time in order to prevent freezing.